The drilled head bolt is only needed when you are using 1958 or earlier rockers on a 1959-62 engine.

As per Pre '68 Dave, would stand to reason from what i've seen. BTW, I do have one of those bolts.


BC
1960 Chevy C10 driver 261 T5 4.10 dana 44 power loc
1949 GMC 250 project in waiting
1960 C60 pasture art
Retired GM dealer tech. 1980 - 2022